This invention relates to a novel diamide derivative of an .alpha.-amino acid. The present invention is also directed to a method for selectively transporting cupric ions contained in a first liquid to a second liquid using the above diamide.
Separation of cupric ions from other heavy metal ions is a very important technique utilized for the recovery and concentration thereof. There are a lot of known extractants and ion transporting agents (ionophores) used for the separation of specific metal ions. An ionophore to be utilized for continuously transporting specific ions contained in a first liquid to a second liquid is required to selectively capture cupric ions. In addition, it is important that the ionophore should release the captured ions to the second liquid in order to effectively perform the continuous transportation of the ions. Known extractants and ionophores, however, are not satisfactory for cupric ions with respect to selectivity or efficiency.